Additive manufacturing of traditional ceramic powder via selective laser sintering with cold isostatic pressing

For improving the final density of traditional ceramic products via selective laser sintering (SLS), cold isostatic pressing (CIP) technologies were introduced into the process. The proposed approach in the work combined spray drying with mechanical mixing by which we prepared a kind of compound powder consisting of epoxy resin E06 (10 wt %) and kaolin so as to get a good fluidity for SLS. At the first step, SLS products reached the highest density of about 0.76 g/cm(3) when the laser energy density was 0.3575 J/mm(2), which facilitated the next operation and improvement of final density. Then, a soft polymer canning was prepared for CIP around the surface of SLS kaolin ceramic products using pre-vulcanized natural rubber latex RTV-2, gelation, and film. Following that, SLS green bodies were pressed with a holding pressure of 50 MPa. Based on thermal gravity curve of epoxy resin E06, green bodies were debinded and furnace-sintered. We experimented on different laser energy densities which had similar effects on densification of kaolin products in CIP, debinding, and sintering. Finally, the density of kaolin products reached 2.65 g/cm(3) after high-temperature sintering process. Field emission scanning electron microscopy was used to analyze the densification evolvement in each stage of process and the fracture mechanism. The study showed a positive and practical approach to fabricate traditional ceramic products with complex shape by an additive manufacturing method of SLS.